Vol. 11, Issue 5, Part C (2025)

Data analysis was conducted using Pearson correlation and multiple regression techniques in SPSS. The findings reveal significant relationships between differential parental treatment and personality divergence, with birth order moderating this association. Specifically, eldest siblings tended to score higher on conscientiousness and leadership traits, while youngest siblings exhibited greater openness and extraversion. Peer influence emerged as a strong predictor of divergence, particularly affecting traits such as agreeableness and neuroticism.

The study highlights that while genetic and shared environmental factors are influential, non-shared experiences—particularly variations in parenting and peer relationships—play a critical role in the differentiation of personality among siblings. These results have theoretical implications for understanding personality development through a contextual lens and practical implications for parenting practices, educational guidance, and psychological interventions aimed at minimizing maladaptive sibling rivalry and fostering individual growth. Limitations of the study include its cross-sectional design and reliance on self-report measures. Future research could benefit from longitudinal designs and multi-informant approaches to validate these findings further.